Problem: $-10kl + km - 4k - 10 = 4l + 1$ Solve for $k$.
Solution: Combine constant terms on the right. $-10kl + km - 4k - {10} = 4l + {1}$ $-10kl + km - 4k = 4l + {11}$ Notice that all the terms on the left-hand side of the equation have $k$ in them. $-10{k}l + 1{k}m - 4{k} = 4l + 11$ Factor out the $k$ ${k} \cdot \left( -10l + m - 4 \right) = 4l + 11$ Isolate the $k$ $k \cdot \left( -{10l + m - 4} \right) = 4l + 11$ $k = \dfrac{ 4l + 11 }{ -{10l + m - 4} }$